Compressor with mufflers

ABSTRACT

Disclosed herewith is a compressor with mufflers. The compressor comprises a drive unit, a compression unit, at least a pair of exhaust mufflers, a coolant exhaust conduit, and a connecting conduit. The drive unit generates power. The compression unit sucks, compresses and exhausts coolant using power transmitted from the drive unit. The exhaust mufflers temporarily store coolant exhausted from the compressing unit. The coolant exhaust conduit is connected to one of the exhaust mufflers to guide the exhaust of coolant to the outside. The connecting conduit connects the exhaust mufflers to each other to cancel out noises during the recombination of divided coolant in one of the exhaust mufflers.

CLAIM OF PRIORITY

[0001] This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for Compressor with Discharge Muffler earlier filed in the Korean Industrial Office on Dec. 11, 2000 and there duly assigned Serial No. 75129/2000 by that Office.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to compressors used for refrigerators or the like, and more particularly to a compressor that is provided with a plurality of exhaust mufflers to reduce pressure pulsation generated during the exhaust of coolant.

[0004] 2. Description of the Prior Art

[0005] In general, a compressor is an apparatus, which is applied to the refrigeration cycle of a refrigerator or the like (in which coolant undergoes a compression process, a condensing process, an expansion process and an evaporation process, sequentially), and compresses low-temperature and low-pressure coolant into high-temperature and high-pressure coolant. Such a compressor may be classified into a linear compressor or reciprocating compressor according to its operating movement.

[0006] A conventional reciprocating compressor is comprised of a sealed container for constituting the outside of the compressor, a drive unit mounted in the sealed container for generating power, and a compression unit for sucking, compressing and exhausting coolant using power generated by the drive unit.

[0007] The drive unit is mounted in the upper portion of the interior of the sealed container. The drive unit is comprised of a stator, a rotor, and a rotating shaft having an eccentric portion at its lower end. The rotating shaft is forcibly inserted into the center portion of the rotor, thus being rotated, together with the rotor.

[0008] The compression unit is disposed in the lower portion of the interior of the sealed container. The compression unit is comprised of a cylinder head provided with suction and exhaust chambers for guiding the suction and exhaust of coolant, a cylinder block assembled with the cylinder head at its front end and provided with a compression chamber, a piston reciprocated through the compression chamber, and a connecting rod connected to the piston through an eccentric shaft for converting rotating movement into linear movement.

[0009] In addition, a suction muffler is situated just over the cylinder head to reduce noise generated during the inflow of coolant. A coolant suction conduit is connected to the suction muffler. Two exhaust mufflers are mounted at two positions under the cylinder block to be connected to the exhaust chamber so as to reduce pressure pulsation generated during the exhaust of high-pressure coolant. A coolant exhaust conduit is connected to one of the exhaust mufflers. One exhaust muffler connected to the coolant exhaust conduit is constructed in a space expansion type, while the other exhaust muffler not connected to the coolant exhaust conduit is constructed in a Helmholtz resonator type.

[0010] When the conventional reciprocating compressor constructed as described above is powered on, the rotating shaft is rotated together with the rotor, and the piston connected to the eccentric portion through the connecting rod is reciprocated through the compression chamber. Accordingly, coolant passes through the suction muffler and the suction chamber of the cylinder head, and flows into and is compressed in the compression chamber. Continuously compressed coolant is exhausted to the exhaust chamber of the cylinder head and the exhaust muffler.

[0011] Low-pressure coolant sucked by the movement of the piston toward the bottom dead center is compressed by the movement of the piston toward the top dead center, and compressed coolant is exhausted to the exhaust chamber of the cylinder head. A portion of compressed coolant is sent to the space expansion type exhaust muffler and the remaining portion is sent to the Helmholtz type exhaust muffler, so the pressure pulsation of coolant is reduced. In this case, owing to the pressure difference during the movement of the piston toward its bottom dead center, compressed coolant in the Helmholtz resonance type muffler passes through the exhaust chamber of the cylinder head, enters the space expansion type exhaust muffler, and thereafter is exhausted to the outside.

[0012] However, in the conventional reciprocating compressor, compressed coolant in the Helmholtz resonance type exhaust muffler passes through the exhaust chamber of the cylinder bead and enters the space expansion type exhaust muffler, so the peak of pressure pulsation is changed during the recombination of coolant, resulting in the problem of creating a noise having a different frequency band.

[0013] Additionally, many factors, such as the volume of the exhaust muffler affecting the natural frequency of the Helmholtz resonance type exhaust muffler and the length and sectional area of the coolant passage connecting the exhaust chamber and the exhaust muffler, should be taken into account so as to reduce a noise generated in the exhaust chamber of the cylinder head, thus making the adjustment of the factors difficult to achieve.

SUMMARY OF THE INVENTION

[0014] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a compressor with mufflers, which is capable of considerably reducing the exhaust noises of coolant in such a way that noises created in the exhaust mufflers by pressure pulsation are cancelled out by destructive interference during the recombination of coolant by directly connecting the exhausting mufflers to one another.

[0015] In order to accomplish the above object, the present invention provides a compressor, comprising: a drive unit for generating power; a compression unit for sucking, compressing and exhausting coolant by power transmitted from the drive unit; at least a pair of exhaust mufflers in which coolant exhausted from the compressing unit is temporarily stored; a coolant exhaust conduit connected to one of the exhaust mufflers to guide the exhaust of coolant to the outside; and a connecting conduit connecting the exhaust mufflers to each other to cancel out noises during the recombination of divided coolant in one of the exhaust mufflers.

[0016] The connecting conduit is preferably constructed to have a length such that a first noise in a first exhaust muffler of the exhaust mufflers is allowed to be opposite in phase to a second noise in a second exhaust muffler after being transmitted to the second exhaust muffler.

[0017] Under the conditions that the frequency bands of the noises generated in the exhaust mufflers are 350 to 600 Hz and the transmission speed of a noise in coolant is 161 m/s, the connecting conduit preferably has a length ranging from 13.4 to 23 cm.

[0018] In addition, the present invention provides a compressor, comprising: a drive unit for generating power; a compression unit for sucking, compressing and exhausting coolant utilizing power transmitted from the drive unit; at least a pair of exhaust mufflers in which coolant exhausted from the compressing unit is temporarily stored; a coolant exhaust conduit connected to one of the exhaust mufflers to guide the exhaust of coolant to the outside; at least a pair of coolant passages each connecting the compression unit to each of the exhaust mufflers, the coolant passages having different lengths so that noises of coolant have opposite phases after the coolant passes through the coolant passages; and a connecting conduit connecting the exhaust mufflers to each other to cancel out the noises having opposite phases during the recombination of divided coolant in one of the exhaust mufflers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0020]FIG. 1 is a partial cross-section showing a compressor with mufflers in accordance with an embodiment of the present invention;

[0021]FIG. 2 is a cross-section taken along line II-II of FIG. 1;

[0022]FIG. 3 is a cross-section taken along line III-III of FIG. 2;

[0023]FIG. 4 is a diagram showing the operation of the compressor of the present invention in which the exhaust noises of coolant are reduced; and

[0024]FIG. 5 is a bottom view showing another compressor with mufflers in accordance with another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Reference now should be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.

[0026] A reciprocating compressor in accordance with the present invention is comprised of a sealed container 10 for containing oil in the lower portion of its interior, a drive unit 20 for generating power by the application of electricity, and a compression unit 30 for sucking, compressing and exhausting coolant using power generated by the drive unit 20.

[0027] The sealed container 10 constitutes the exterior of the reciprocating compressor, and is fabricated by airtightly attaching an upper container part 11 and the lower container part 12 to each other.

[0028] The drive unit 20 is mounted in the upper portion of the interior of the sealed container 10. The drive unit 20 is comprised of a stator 21 for generating a magnetic field by the application of electricity, a rotor 22 rotatably mounted in the stator 21, and a rotating shaft 23 forcibly fitted into the rotor and provided with an eccentric portion at its lower end.

[0029] The compression unit 30 is disposed in the lower portion of the interior of the sealed container 10. The compression unit 30 is comprised of a cylinder block 31 provided with a compression chamber 31 a to suck, compress and exhaust coolant by the reciprocating movement of a piston 33, a connecting rod 34 connecting the piston 33 and the eccentric portion 24, a cylinder head 32 situated in front of the cylinder block 31 and provided with a sucking chamber 32 a and the exhaust chamber 32 b. Reference numeral “25” designates a support bearing that is rested on the cylinder block 31 to support the rotation of the rotating shaft 23 and the rotor 22. Reference numeral “40” designates a suction muffler that is situated over the cylinder head 32 to reduce noise generated by the inflow of coolant. A coolant suction conduit 13 is connected to the suction muffler 40 to guide coolant from the outside to the sealed container 10.

[0030] The exhaust mufflers 50L and 50R are provided under the cylinder block 31 so as to reduce pressure pulsation during the exhaust of compressed coolant through the exhaust chamber 32 b of the cylinder head 32. The detailed structure of the exhaust mufflers 50L and 50R will be described with reference to FIGS. 2 and 3.

[0031] First of all, the exhaust mufflers 50L and 50R are symmetrically arranged under the cylinder block 31 at two positions, and secured to the cylinder block 31 by means of bolts. A damping space 51 is formed in the interior of each of the exhaust mufflers 50L and 50R.

[0032] Coolant passages 52L and 52R are each formed in the cylinder block 31 to connect the exhaust chamber 32 b (refer to FIG. 1) of the cylinder head 32 and each of the exhaust mufflers 50L and 50R. A coolant exhaust conduit 14 is connected to one of the exhaust mufflers 50L and 50R to exhaust coolant to the outside, that is, the refrigerating cycle (in this embodiment, as shown in FIG. 3, the coolant exhaust conduit 14 is connected to the right exhaust muffler 50R).

[0033] A connecting conduit 60 connects the exhaust mufflers 50L and 50R to each other so as to diminish noises by destructive interference during the recombination of the coolant. As a result, one end 61 of the connecting conduit 60 is connected to the left exhaust muffler 50L and the other end 62 of the connecting conduit 60 is connected to the right exhaust muffler 50R, so the two exhaust mufflers 50L and 50R communicate with each other by the connecting conduit 60.

[0034] In this case, the connecting conduit 60 should be constructed to have a length, which allows a noise in the left exhaust muffler 50L to be opposite in phase to a noise in the right exhaust muffler 50R.

[0035] The determination of the length of the connecting conduit 60 will be described hereinafter.

[0036] In order to allow the noise in the left exhaust muffler 50L to be opposite in phase to the noise in the right exhaust muffler 50R after passing through the connecting conduit 60, the length of the connecting conduit 60 should satisfy the following equation:

L=λ/2

[0037] where L is the length of the connecting conduit 60, λ is c/f, c is the frequency of a noise, and f is the transmission speed of a noise in coolant.

[0038] By way of example, under the conditions that the frequency “c” of the noises generated in the exhaust mufflers 50L and 5OR are 350 to 600 Hz and the transmission speed “f” of a noise in coolant R134 a generally applied to a refrigerator is 161 m/s (at 100° C.), the length L of the connecting conduit 60 is preferably 13.4 to 23 cm.

[0039] As a result, after the noise in the left exhaust muffler 50L is transmitted to the right exhaust muffler 50R through the connecting conduit 60, the phase of the noise from the left exhaust muffler 50L becomes opposite to that of the noise in the right exhaust muffler 50R. This causes the noise in the left exhaust muffler 50L to cancel out the noise in the right exhaust muffler 50R by destructive interference.

[0040] In the reciprocating compressor, a noise having a certain frequency band can be easily eliminated by varying the length L of the connecting conduit 60. Additionally, it is apparent that if the inner diameter of the connecting conduit 60 as well as the length L of the connecting conduit 60 is suitably adjusted, a noise having a certain frequency band can be easily eliminated.

[0041] Hereinafter, the operation and effects of the reciprocating compressor of the present invention are described in detail.

[0042] When the reciprocating compressor of the present invention is powered on, the rotor 22 is rotated with the rotating shaft 23 at a high speed. This rotating movement is converted into the linear movement of the piston 33 through the connecting rod 33.

[0043] Accordingly, the piston 33 is reciprocated through the compression chamber 31 a. When the piston 33 is moved toward its bottom dead center, or is at its suction stage, low-pressure coolant is sucked to the compression chamber 31 a through the suction muffler 40 and the suction chamber 32 a; whereas the piston 33 is moved toward its top dead center, or is at its exhaust stage, compressed coolant is exhausted to the exhaust chamber 32 b and the damping spaces of the exhaust mufflers 50L and 50R and continues to be exhausted out of the sealed container 10 through the coolant exhaust conduit 14. This operation is performed one time for a single revolution of the rotating shaft 23.

[0044] In the meantime, a portion of compressed coolant exhausted to the exhaust chamber 32 b is sent to the left exhaust muffler 50L through the left coolant passage 52L and the remaining portion is sent to the right exhaust muffler 50R through the right coolant passage 52R, so pressure pulsation is reduced. In this state, coolant is exhausted to the outside through the coolant exhaust conduit 14. The compressed coolant sent to the left exhaust muffler 50L is exhausted to the right exhaust muffler 50R through the connecting conduit 60. During this process, the noises of the compressed coolant are cancelled out.

[0045] As shown in FIG. 4, a first noise “A” having a sine wave is created while compressed coolant is exhausted to the exhaust chamber 32 b (refer to FIG. 1) of the cylinder head 32, and 18 the first noise “A” of a certain frequency band created by pressure pulsation is transmitted to the left and right exhaust mufflers 50L and 50R while the compressed coolant is sent to the left and right exhaust mufflers 50L and 50R. In other words, while the compressed coolant is sent to the left and right exhaust mufflers 50L and 50R, the second and third noises “B” and “C”having the same frequency as that of the first noise are created.

[0046] Thereafter, the compressed coolant sent to the right exhaust muffler 50R is directly exhausted to the outside through the coolant exhaust conduit 14; while the compressed coolant sent to the left exhaust muffler 50L is sent to the right exhaust muffler 50R through the connecting conduit 60 and recombined with the compressed coolant remaining in the right exhaust muffler 50R.

[0047] While the noise “B” in the left exhaust muffler 50L, together with the compressed coolant, is transmitted to the right muffler 50R through the connecting conduit 60, the noise “B” becomes a noise “D” that has a phase difference of 180° in comparison with the noise “C” in the right exhaust muffler 50R.

[0048] As a result, while the compressed coolant in the left exhaust muffler 50L is recombined with the compressed coolant in the right exhaust muffler 50R through the connecting conduit 60, the noises are cancelled out by destructive interference. Consequently, the entire exhaust noise of the compressed coolant is considerably reduced.

[0049] Meanwhile, although the noises are described as being canceled out by the adjustment of the length L of the connecting conduit 60, the object of the present invention can be achieved by the adjustment of the lengths L1 and L2 of the coolant passages 52L and 52R that connect the exhaust chamber 32 b (refer to FIG. 1) to the exhaust muffler 50L and the exhaust chamber 32 b (refer to FIG. 1) to the exhaust muffler 50R, respectively.

[0050] In more detail, in order to allow the phases of noises to be opposite after the compressed coolant is sent to the exhaust mufflers 50L and 50R through the coolant passages 52L and 52R, the length LI of the left coolant passage 52L connecting the exhaust chamber 32 b to the left exhaust muffler 50L and the length L2 of the right coolant passage 52R connecting the exhaust chamber 32 b to the right exhaust muffler 50R are designed to be different from each other (in this embodiment, the length L1 of the left coolant passage 52L is designed to be longer than the length L2 of the right coolant passage 52R, that is, L1>L2).

[0051] Accordingly, the noise generated during the exhaust of coolant from the exhaust chamber 32 b of the cylinder head 32 is transmitted to the exhaust mufflers 50L and 50R through the coolant passages 52L and 52R of different lengths L1 and L2, so the noises in the left and right mufflers have opposite phases.

[0052] The compressed coolant sent to the left exhaust muffler 50L is sent to the right exhaust muffler 50R through the connecting conduit 60, recombined with the coolant remaining in the right exhaust muffler 50R, and discharged from the sealed container 10, together with the coolant remaining in the right exhaust muffler 50R. In this case, the noise in the left exhaust muffler 50L, together with the compressed coolant, is transmitted to the right exhaust muffler 50R through the connecting conduit 60, so the noise transmitted from the left exhaust muffler 50L and the noise in the right exhaust muffler 50R are canceled out by destructive interference. Accordingly, the entire exhaust noises of the compressed coolant are considerably reduced.

[0053] As described above, the present invention provides a compressor with exhaust mufflers in which a pair of exhaust mufflers is symmetrically arranged under its cylinder block, a coolant exhaust conduit is connected to one of the exhaust mufflers and the exhaust mufflers are connected by a connecting conduit to communicate with each other. In this case, the length of the connecting conduit is designed so as to allow the phase of the noise of coolant contained in one of the exhaust mufflers to be opposite to the phase of the noise of the coolant contained in the other exhaust muffler after the transmission of the noise of the former exhaust muffler. As a result, noises are cancelled out by destructive interference while the compressed coolant sent to a pair of exhaust mufflers are recombined with each other through the connecting conduit, so the entire noises of compressed coolant are considerably reduced. Additionally, a noise having any frequency band can be easily eliminated by varying the length of the connecting conduit.

[0054] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

What is claimed is:
 1. A compressor, comprising: a drive unit for generating power; a compression unit for sucking, compressing and exhausting coolant by power transmitted from said drive unit; at least a pair of exhaust mufflers in which coolant exhausted from said compressing unit is temporarily stored; a coolant exhaust conduit connected to one of said exhaust mufflers to guide the exhaust of coolant to the outside; and a connecting conduit connecting said exhaust mufflers to each other to cancel out noises during the recombination of divided coolant in one of said exhaust mufflers.
 2. The compressor according to claim 1, where said connecting conduit is constructed to have a length such that a first noise in a first exhaust muffler of said exhaust mufflers is allowed to be opposite in phase to a second noise in a second exhaust muffler after being transmitted to said second exhaust muffler.
 3. The compressor according to claim 1, wherein under the conditions that the frequency bands of the noises generated in said exhaust mufflers are 350 to 600 Hz and the transmission speed of a noise in coolant is 161 m/s, said connecting conduit has a length ranging from 13.4 to 23 cm.
 4. A compressor, comprising: a drive unit for generating power; a compression unit for sucking, compressing and exhausting coolant utilizing power transmitted from said drive unit; at least a pair of exhaust mufflers in which coolant exhausted from said compressing unit is temporarily stored; a coolant exhaust conduit connected to one of said exhaust mufflers to guide the exhaust of coolant to the outside; at least a pair of coolant passages each connecting said compression unit to each of said exhaust mufflers, said coolant passages having different lengths so that noises of coolant have opposite phases after the coolant passes through said coolant passages; and a connecting conduit connecting said exhaust mufflers to each other to cancel out said noises having opposite phases during the recombination of divided coolant in one of said exhaust mufflers. 